scholarly journals Algorithm for the determination of the angle of repose in bulk material analysis

2021 ◽  
Vol 383 ◽  
pp. 598-605
Author(s):  
Dominik Müller ◽  
Eric Fimbinger ◽  
Clemens Brand
Author(s):  
И.В. Бачериков ◽  
Б.М. Локштанов

При проектировании открытых и закрытых хранилищ измельченных сыпучих материалов древесных материалов, таких как щепа и опилки, большое значение имеет угол естественного откоса (статический и динамический) этих материалов. В технической литературе приводятся противоречивые сведения о величине этих углов, что приводит к ошибкам при проектировании складов. В справочных данных не учитываются условия, в которых эксплуатируются емкости для хранения сыпучих материалов, свойства и состояние этих сыпучих материалов. В свою очередь, ошибки при проектировании приводят к проблемам (зависание, сводообразование, «затопление» и т. д.) и авариям при эксплуатации бункеров и силосов на производстве. В статье представлены сведения, посвященные влиянию влажности и температуры на угол естественного откоса сыпучих материалов. На основании лабораторных и натурных экспериментов, проведенных с помощью специально разработанных методик и установок, была скорректирована формула для определения углов естественного откоса (статического и динамического) для измельченных древесных материалов в зависимости от их фракционного и породного состава, влажности (абсолютной и относительной) и температуры. При помощи скорректированной формулы можно определить угол естественного откоса древесных сыпучих материалов со среднегеометрическим размером частицы от 0,5 мм до 15 мм (от древесной пыли до технологической щепы) в различных производственных условиях. Статья может быть полезна проектировщикам при расчете угла наклона граней выпускающей воронки бункеров и силосов предприятий лесной отрасли и целлюлозо-бумажной промышленности. In the design of open and closed storage warehouses chopped wood materials for bulk materials such as wood chips and sawdust, great importance has an angle of repose (static and dynamic) of these materials. In the technical literature are conflicting reports about the magnitude of these angles, which leads to errors in the design of warehouses. In the referencesdoes not take into account the conditions under which operated capacities for storage of bulk materials, and properties and condition of the bulk material. The design errors lead to problems (hanging, arching, «flooding», etc.) and accidents in the operation of hoppers and silos at the mills. The article provides information on the impact of humidity and temperature on the angle of repose of granular materials. On the basis of laboratory and field experiments, conducted with the help of specially developed techniques and facilities has been adjusted formula for determining the angle of repose (static and dynamic) for the shredded wood materials depending on their fractional and species composition, humidity (absolute and relative) and temperature. It is possible, by using the corrected formula, to determine the angle of repose of loose wood materials with average particle size of from 0.5 mm to 15 mm (wood dust to pulpchips) in various operating conditions. The article can be helpful to designers in the calculation of the angle of inclination of the funnel faces produces bunkers and silos forest industries and pulp and paper industry.


INDIAN DRUGS ◽  
2019 ◽  
Vol 56 (08) ◽  
pp. 27-37
Author(s):  
S. Bhusari ◽  
A Chaudhary ◽  
G Shrangare ◽  
M. Rindhe ◽  
P. Wakte ◽  
...  

The aim of the present study is to determine the physicochemical properties of Picroside-II, a phytochemical obtained from the herb of Picrorhiza kurroa. The solubility study of picroside-II shows that it has better solubility in water up to 2.46 mg/mL than organic solvents. The solubility of picroside-II in linseed oil was found to be 71.46 mg/mL. The solubility of Picroside-II in surfactant like Transcutol P and labrasol was found to be 907.80 and 535.90 mg/mL, respectively. Picroside-II had a melting point in the range of 130 to 135°C. The log P value of picroside-II was estimated using shake flask method followed by UV analysis. The log P value of picroside-II was found to be -0.09675, which shows its hydrophilicity. The pKa determination of picroside-II was carried out by using UV-visible spectrophotometer and the pKa value was found to be 7.80. The particle size distribution of picroside-II powder was also carried out and the maximum particles of picroside-II are in the range of 53-75 μm. Flow properties of picroside-II were also studied. bulk and tapped density of picroside-II powder was found to be 0.149 and 0.248, respectively. The Hausner ratio and compressibility index were also calculated and it was found to be 1.66 and 39.99, which confirm the poor flow properities of picroside-II powder. The angle of repose of picroside-II was found to be 41.08°, which shows the passable flow of picroside-II. Water was found to be the better extractive solvent for picroside-II; the extractive value of picroside-II in water was found to be 9.12%.


2019 ◽  
Vol 30 (10) ◽  
pp. 2110-2116 ◽  
Author(s):  
Michael J. Carr ◽  
Alan W. Roberts ◽  
Craig A. Wheeler
Keyword(s):  

1973 ◽  
Vol 17 ◽  
pp. 44-67 ◽  
Author(s):  
C. L. Grant ◽  
P. A. Pelton

Sampling is a necessary part of the chemical analysis of particulate matter where the objective is to characterize bulk properties since it is usually undesirable or impossible to test an entire lot. The sample must be a miniature replica of the bulk material at least in respect to those features being tested. In other words, the sample must be representative to permit extrapolation from the sample to the bulk.There is error associated with sampling particulate material, but this sampling error is only one component of the total error associated with an analytical result. Sample preparation and determination of the property being tested are two other major sources of error, These three errors combine as the squares of their standard deviations, i.e., their variances, to produce the total analytical error. Very often, sampling error is the largest of the three and, therefore, contributes a disproportionately large share to the total error.


Processes ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 222
Author(s):  
Jakub Hlosta ◽  
Lucie Jezerská ◽  
Jiří Rozbroj ◽  
David Žurovec ◽  
Jan Nečas ◽  
...  

This paper’s goal was to select methods and a calibration procedure which would lead to the determination of relevant parameters of a discrete element method (DEM) and virtual material creation. Seven particulates were selected with respect to their shape (spherical and non-spherical), size and density. The first calibration experiment involved “packing test” to determine the shape accuracy and bulk density of virtual packed particulates. The series of simulations were compared with real experiments, and the size, shape and density of virtual particles were optimized. Using three apparatuses, the input parameter values were experimentally determined for a contact model that defines the behavior of particulates in DEM simulations. The research part of the paper examines the influence of factors such as particle number; pile formation method; and the method of evaluation of the angle of repose on the process of the calibration of virtual material. The most reproducible results were achieved by the “pilling” method and by the rotating drum—both evaluated by the geometric method. However, it is always advisable to make an overall visual comparison of the slope shape between the calibration simulation and the experimental curves. The bowl’s diameter to particle size ratio should be greater than 25, and the calibration experiment should contain approximately 4000 particles to ensure representative results during angle of repose calibration experiment.


Author(s):  
EMAN A. MAZYED ◽  
SHERIN ZAKARIA

Objective: The present investigation aims to formulate and evaluate proniosomes of clopidogrel bisulphate for improving its dissolution characteristics. Methods: The slurry method was used for the preparation of proniosomes of clopidogrel using cholesterol, sorbitan monostearate (Span 60) and maltodextrin as a carrier. Clopidogrel proniosomes were evaluated for their entrapment efficiency and in vitro drug release. The best formula (F1) that achieved maximum drug release was further evaluated by measurement of the angle of repose, morphological examination, determination of vesicle size, determination of zeta potential, Fourier transform infrared spectroscopy and differential thermal analysis. The in vivo behavior of the selected proniosomal formula (F1) was studied by measuring the antiplatelet activity in adult male mice. Results: The entrapment efficiency of clopidogrel proniosomes was in the range of 83.04±1.99 to 90.14±0.30. % drug released from proniosomal formulations was in the range of 79.73±0.35 to 97.70±1.10 % within 4 h. Clopidogrel proniosomes significantly enhanced the in vitro release of clopidogrel compared with the plain drug that achieved 61.77±2.22 % drug release. F1 significantly (p ≤ 0.001) increased the bleeding time and bleeding volume and significantly (p ≤ 0.05) prolonged prothrombin time and decreased prothrombin activity and increased the international normalized ratio (INR) compared to plain clopidogrel. Conclusion: The present investigation introduced proniosomes as a promising carrier for clopidogrel that could enhance its dissolution and pharmacological effect.


2003 ◽  
Vol 58 (8) ◽  
pp. 809-812 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Oleg L. Tok ◽  
Amin Badshah

The crystal structure of tetra(propyn-1-yl)silane, Si(C≡CMe)4 1, has revealed a completely asymmetric molecule (point group C1). Since this finding concerns a single crystal, the bulk material of 1 was studied by solid-state 29Si and 13C MAS NMR. This confirmed the result of the X-ray analysis, and by comparison with previous NMR measurements of the tin analogue 1(Sn) it is concluded that 1 and 1(Sn) must have very similar solid-state structures which are in contrast to those known for other tetra(alkyn-1-yl)silicon and -tin compounds. The NMR data set of 1 in solution was completed by determination of the magnitude of coupling constants 1J(13C,13C).


Sign in / Sign up

Export Citation Format

Share Document